Thank you for all that info. I did have a negative antibody test a couple weeks before the vaccine was taken. And, while I did have a household covid exposure during that month time-frame, we separated completely, and I got tested multiple times throughout (all negative), so I'm fairly sure these antibodies are from the vaccine.
Would you consider this the same level of immunity as anyone who had antibodies from covid itself, or you'd think this is less? I know in some cities, right or wrong, the schools and other local establishments consider covid antibodies to be a good level of immunity and thus have different policies for those individuals upon exposures, etc.
I may try to test again somewhere that provides the numbers, as maybe that will be helpful.
Lastly, will I begin to gain that added second dose protection within 3 days of receiving it? (Curious because my scheduled shot is Monday before Purim).
Shimshon, you're asking intelligent questions, so you've probably been following the news on covid for a while already, and you know that as our knowledge about the virus evolves, the public health guidance also changes. I'm not sure that the same can be said for those establishments that devise policy based on antibody levels. Although that was considered a possibility back in May? June? I can't remember exactly when. But since then, public health advice is that the value of measuring antibody level is that it helps a physician decide how to treat a patient's current symptoms, and that it shouldn't be used to draw conclusions about a person's immunity to the virus. So there's no reason for you to test again.
With someone who has covid, antibodies also are produced after a time lag after infection.
"Most persons infected with SARS-CoV-2 display an antibody response between day 10 and day 21 after infection. Detection in mild cases can take longer time (four weeks or more) and in a small number of cases antibodies (i.e., IgM, IgG) are not detected at all (at least during the studies’ time scale)."
https://www.ecdc.europa.eu/en/covid-19/latest-evidence/immune-responsesSo the fact that you developed antibody two weeks after injection is similar to what happens in natural covid infection (and in any infection, and after any vaccination). But two important points: The quote above refers to detection of antibodies, not elevation of antibodies to a level high enough to fight infection. We just don't know yet if there's some threshold of antibodies needed to fight infection. And there is a large range in response (as little as 10 days, as much as 21 days in different people).
This variation is important to keep in mind when you think about your own individual immunity. Clinical trials look at tens of thousands of people, and the results they give tell us what will happen with the average human. But because of the variation in how individuals respond, they can't tell us anything about any one particular person. For example, it's possible that you're a bit faster than average in developing an antibody response, but a bit slower than average in developing a T cell response, and both are needed for complete immunity. It's just not meaningful to try to calculate your own level of immunity based on antibody level at this time.
Compare it to this: We know that about 15% of smokers get lung cancer. That refers to smokers as a group. But we can't generally predict for one individual smoker whether they'll fall into the 15% who do or the 85% who don't get lung cancer.
Re: Purim: You should definitely be marbim b'simcha, but with a mask on, socially distancing, etc. The mask at least is appropriate for Purim anyway. You should assume that you don't have complete immunity until 2 weeks after the second dose.
This is not to say that you won't have complete immunity, because remember there's a lot of variation in how individual people respond to the vaccine and to the virus. Immunity probably increases over the entire time interval, so it's not as if it's zero all along, and then bam! 2 weeks post-vaccination it goes up to 95%. So your chances of getting infected one week after the second vaccine is probably very very low. But the recommendation is based on the study of large groups of people, and how likely they were to get infected, and that seems to reach a low plateau 2 weeks post-vaccine.
A second reason for maintaining precautions at that time is because .... imagine taking all these precautions, going through two vaccines, and then punkt! you come down with covid. The irony would be too much to bear...
